The Bulgarian Football Union has described Gareth Southgate's racism concerns as "groundless, inappropriate and unnecessary".
Speaking in the wake of an alleged incident during England's 4-0 win over Bulgaria at Wembley last weekend, manager Southgate said racist abuse was a "concern" ahead of the return game in Sofia in October.
England's players are also understood by Sky Sports to have held discussions over whether to walk off the pitch in future if any of them are the subject of racist comments.
But the BFU has written to UEFA and Southgate's boss, Football Association chairman Greg Clarke, to express its unhappiness at his comments.
Southgate's words came after Raheem Sterling was the target of alleged abuse at Wembley last Saturday.
An away supporter was ejected from the ground after a steward overheard him making an alleged racist comment towards the Manchester City forward during the game.
"Yes, it is a concern," Southgate said about the return game. "It's something that we've already planned.
"We've already planned what our schedule looks like and we're going to discuss it with the players before we go, because we're aware that there is history there and we want to make sure that we're all prepared for what might happen and how we want to respond."
Next month's qualifier will be England's first trip to Bulgaria since September 2011, when a 3-0 win was overshadowed by racist abuse in Sofia.
Ashley Young was subjected to monkey chants during that game, but the Bulgarian Football Union only received a 40,000 euros (£35,500) fine by UEFA for "discriminatory" chanting and for the lighting and throwing of fireworks.
But the BFU has reacted angrily to Southgate's comments.
"The president of the Bulgarian Football Union Borislav Mihaylov sent an official letter to the UEFA General Secretary Mr. Theodore Theodoridis and the chairman of the English FA Mr. Greg Clarke expressing his indignation and disappointment following the public comments by Mr. Gareth Southgate and the suggestions that the English players will be subject to racial abuse by the Bulgarian supporters in the upcoming European qualifier in Sofia on October 14th," a statement read.
"The BFU views such behaviour as groundless, inappropriate and unnecessary prior to the important and exciting football game that Bulgarian fans have been looking to in the past year.
"We have not received any official information regarding discriminatory language used by a Bulgarian supporter at Wembley Stadium.
"Even if this were the case, however, we believe that generalisations and the creation of needless tension by official members of the English team is absolutely unacceptable and in contradiction with the spirit of mutual respect and fair play, the core values of both UEFA and the BFU."
The Vasil Levski National Stadium will already be partially closed for England's latest visit due to the racist behaviour of their supporters in the 2-1 loss in the Czech Republic in June.
At least 5,000 seats will be unused for the visit of Southgate's men and will instead display a banner with the wording '#EqualGame'.
Bulgaria's return fixture against the Czechs is also due to be played at a partially-closed ground due to racist behaviour in the 3-2 home loss to Kosovo in their other June fixture.